This invention relates to an antenna, and, in particular, relates to a glass antenna which is to be mounted on a vehicle window glass and is suitable for receiving digital terrestrial TV broadcast signals and UHF analog TV broadcast signals.
For vehicle glass antennas, antennas to be mounted in the spaces upper or lower than heating conductive lines of defogger on rear window glasses have been developed and widely known so far (for example, refer to JP 2008-124822 A, JP 2005-354139 A, JP 2008-135944 A, and JP 2007-150966 A). To mount such an antenna on a rear window glass, the space for mounting the antenna is limited because defogging heating lines are arranged over most of the area of the rear window glass.
Besides, to improve the antenna sensitivity of a rear window glass antenna, the number of elements is increased or vertical elements are added within the defogger area. Accordingly, the antenna pattern has been more complex, so good looks and the field of view can not be achieved. In addition, the increase in the number of element lines has caused a problem of increase in time and costs for tuning development.
If an antenna is mounted on a front window glass to improve its receiving performance, a simpler antenna pattern and a more compact size are required for the antenna to ensure a wider field of view through the front window glass.
All of the antennas in the above-referenced patent documents are large-sized antennas to be mounted on rear window glasses and are not compact antennas particularly intended to be mounted on front window glasses, for which drivers' field of view is considered to be more important. Accordingly, a more compact and simpler antenna is desired that is to be mounted on a front window glass and does not interfere with the driver's field of view.
An object of this invention is to provide an antenna with simple pattern which ensures required sensitivity and can be arranged on a front window glass.